A: Hello, thanks for reaching out!

Yes on both counts — and the second part is automatic, so there's nothing to configure for the blocking itself.

Set it up as three booking types on the same account: "Morning" at 240 minutes with an availability window of 09:00–13:00, "Afternoon" at 240 minutes on 13:00–17:00, and "Whole day" with Duration set to Custom and 480 minutes, on a 09:00–17:00 window. The whole session has to fit inside the window, so each of those gives you exactly one bookable start time rather than a run of slots, which is what produces the clean morning / afternoon / full-day choice. The Custom duration field takes any number of minutes, so a full day is no problem.

The mutual blocking then takes care of itself. When TidyCal decides whether a slot is free, it checks every booking in your account against that slot's time span — not just bookings on the same booking type — and it compares the full span rather than the start time. So the moment someone takes the morning, the whole-day option disappears from that date because the two overlap, while the afternoon stays open. If someone takes the whole day instead, both half-days vanish. And once both halves are sold, the whole-day option is already gone. This happens on the booking page itself, so nobody even gets as far as submitting a clash.

One setting to leave alone: under Restrictions there's a toggle called "Ignore external calendar conflicts." It's off by default and should stay off. Despite the name it also stops bookings on your other booking types from blocking a slot, which is precisely the behaviour you're relying on here.

If you have any other questions, feel free to reach out to us at [email protected] and we'll be happy to help!